Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 51:

• JAMB 1994

H^- + H_2(I)O → H_2(g) + OH^-_(aq). From the equation above, it can be inferred that the?

A. Reaction is a double decomposition
B. Hydride ion is a reducing agent
C. Hydride ion is an oxidizing agent
D. Reaction is neutralization

Question 52:

• JAMB 1994

MnO_4(aq) + 8H + _(aq) + 5Fe²⁺ → Mn^2+(aq) + 4H₂O_(I). The oxidation number of manganese in the above reaction changed from?

A. +7 to +2
B. +6 to +2
C. +5 to +2
D. +4 to +2

Question 53:

• JAMB 1994

MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from

A. +7 to +2
B. +6 to +2
C. +5 to +2
D. +4 to +2

Question 54:

• JAMB 1995

Which of the following is a redox reaction?

A. KCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)
B. 2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)
C. 3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)
D. H₂CO_3(aq) → H₂O_(I)2- + CO_2(g)

Question 55:

• JAMB 1995

Cr₂O₇^2-_(aq) + 14H⁺_(aq) + 6l^-_(aq) → 2Cr³⁺_(aq) + 3l_(g) + 7H₂O_(I).
The change in the oxidation number of oxygen in the equation above is?

B. 1
C. 2
D. 7